Reducing the Domain Shader/Tessellatorinvocations

ABSTRACT

In accordance with some embodiments, domain shader and/or tessellator operations can be eliminated when they are redundant. By using a corner cache, a check can determine whether a given corner, be it a vertex or a quadrilateral corner, has already been evaluated in the domain shader and/or tessellator and if so, the result of the previous operation can be reused instead of performing unnecessary invocations that may increase power consumption or reduce speed.

BACKGROUND

This relates generally to graphics processing.

In graphics processing a pipeline is implemented in which a series ofsteps are performed on so-called vertices or corners. Primitives may beused to represent a surface being graphically rendered.

Tesselation is the process of subdividing a surface to be graphicallydepicted into smaller shapes. Tesselation breaks down the surface of anobject into manageable triangles.

A Domain shader calculates the properties of each vertex of a subdividedoutput patch. The domain shader receives the hull shader output controlpoints and the tesselator stage output domain locations and outputs avertex position.

The hull shader is invoked once per patch and transforms input controlpoints into output control points that make up a patch. It does some perpatch calculations to provide data for the tessellation stage and thedomain shader.

The term domain shader is generally associated with the DirectXpipeline. Essentially the same function is performed in otherapplication program interfaces used for graphic processing includingOpenGL which commonly refers to the DirectX domain shader as atessellator evaluation shader. In OpenGL, the hull shader is oftencalled the tessellator control shader.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic depiction of a graphics pipeline in accordancewith one embodiment;

FIG. 2 shows a hull shader input control cage on the left and a hullshader output control cage on the right according to one embodiment;

FIG. 3 shows an input control cage on the left which is the same as theinput control cage shown in FIG. 2 but shows a different output controlcage;

FIG. 4 is a schematic depiction of a processor-based system according toone embodiment; and

FIG. 5 is a front elevational view of a hand-held device according toone embodiment.

DETAILED DESCRIPTION

In accordance with some embodiments, domain shader and/or tessellatorredundant operations can be eliminated. By using a corner cache, a checkcan determine whether a given corner (be it a triangle or aquadrilateral corner), has already been evaluated in the domain shaderand/or tessellator. If so, the result of the previous operation can bereused instead of doing unnecessary operation which may increase powerconsumption and/or reduce speed.

In the following discussion, DirectX application program interface (API)terminology is generally used. In all cases, corresponding structuresmay be found in other application program interfaces including OpenGL.In particular, references to a domain shader is applicable to thetessellator evaluation shader in OpenGL and references to the hullshader has applicability to the tessellator Control Shader in OpenGL.Thus the discussion that follows is applicable to any applicationprogram interface used for graphics processing.

A control cage is a low resolution model used by artists to generatesmooth surfaces. By providing a higher degree of tessellation, the levelof graphical detail that can be depicted is greater. However processingspeed may be adversely affected by greater degrees of tessellation.

A patch is a basic unit at a coarse level describing a control cage fora surface. The surface can be any surface that can be described as aparametric function.

The graphics pipeline 10 shown in FIG. 1 may be implemented in agraphics processor as a stand-alone, dedicated integrated circuit, orsoftware, through software implemented general purpose processors, or bycombinations of software and hardware. In some embodiments, elementsdepicted in FIG. 1 with right angle edges can be implemented in hardwareand elements depicted in FIG. 1 with rounded edges can be in software.

The graphics pipeline may be implemented for example in a wirelesstelephone, a mobile hand-held computing device that incorporates a wiredor wireless communication device or any computer. The graphics pipelinemay provide images or video for display to a display device. Varioustechniques can be used to process images provided to the display.

The input assembler 12 reads vertices out of memory using fixed functionoperations, forming geometry, and creating pipeline work items.Automatically generated identifiers enable identifier-specificprocessing. Vertex identifiers and instance identifiers are availablefrom the vertex shader 14 onward. Primitive identifiers are availablefrom the hull shader 16 onward. The control point identifiers areavailable in the hull shader 16.

The vertex shader performs operations such as transformation, skinningor lighting. It may input one vertex and output one vertex. The controlpoint phase is invoked per output control point and each identified by acontrol point identifier.

The hull shader 16 control-point phase outputs one control point perinvocation. The aggregate output is a shared input to the next hullshader phase and to the domain shader 26. Patch constant phases may beinvoked once per patch with shared read input of all input and outputcontrol points. The hull shader 16 outputs edge tessellation factors andother patch constant data. As used herein, edge tessellation factor andedge level of detail with a number of intervals per edge of theprimitive domain may be used interchangeably. Codes are segmented sothat independent work can be done with parallel finishing with a joinstep at the end.

The tessellator 18 may be implemented in hardware or in software. Insome advantageous embodiments, the tessellator may be a softwareimplemented tessellator. The tessellator 18 retrieves encoded domainpoints or (u, v, w) values. A tessellator 18 may receive, from the hullshader, numbers defining how much to tessellate. The tessellator 18generates topologies, such as points, lines or triangles. Tessellator 18may output domain locations.

The domain shader 24 is a programmable stage that uses the domainpoint's (u, v, w) values, supplied by the tessellator 18 to generate areal three-dimensional vertex on a patch. The domain shader 26 evaluatesvertex positions and attributes and optionally displaces the points bylooking up displacement maps. The domain shader 26 may evaluate avertex's normal and other attributes using (u, v, w) values from thetessellator 18. High frequency detail of the patch can be added using adisplacement map. In some embodiments, the domain shader 26 may besoftware implemented.

The domain shader 26 may displace a point using a scalar displacementmap or calculate other vertex attributes. In some cases, the vertexevaluations may involve the determination of a bi-cubic polynomial (orhigher ordered polynomial in general) for positions, calculating partialderivatives or evaluating the tangent and bi-tangent using auxiliarytangent and bi-tangent control cages and taking their cross products,performing a textured lookup with some filtering such as linearfiltering, displacing a point along a normal in the case of scalar valuedisplacements, and displacing a point along the directions that couldpotentially be read from other texture ease in the case of vector valuedisplacements.

The primitive assembler 28 assembles the resulting primitives andprovides the assembled primitives to later stages of the pipeline that,in turn, provide fixed function target rendering, blending, depth andstencil operations.

In some embodiments, the hull shader 16 outputs three or four additional32-bit identifiers packed contiguously to form an array. Three outputsmay be used in the case of triangles and four outputs may be needed inthe case of quadrilaterals. The array identifies the output corners ofan output patch uniquely. Before launching the domain shader invocationsfor the corners, the pipeline queries a corner cache 22 usingcorresponding corner identifiers. If the pipeline does not find an entrycorresponding to that corner, that corner's domain shader getsevaluated. After the domain shader's evaluation is complete, the systemcaches the output of the domain shader for that corner and tags it usingthe corresponding corner identifier.

Conversely if the system finds an entry for a particular corneridentifier, it uses the cached values instead of evaluating a domainshader invocation for that corner. Thus for each triangle orquadrilateral patch, up to three or four entries may be createdcorresponding to three or four corners.

The corner cache may be flushed between draw calls. In aggressiveimplementations, one can give the control when one to flush the cache tothe user, and thus the user can cache the values across draw calls. Thisscenario may help in the situation where a single mesh has multipletypes of patches, such as regular and extraordinary patches, and thereis one draw call corresponding to each type of patch for maximal singleinstruction multiple data (SIMD) utilization.

In some embodiments, an edge cache and a corner cache may be providedseparately in block 22. The edge cache may do the same thing as thecorner cache, namely avoiding unnecessary invocations of the domainshader and/or the tessellator, for edges that have already beenpreviously evaluated.

However, it may be advantageous to have separate corner and edge cachesbecause the flushing cycles for corners and edges are different. Forexample, an edge can only be used twice because only two adjacentpatches would have one common edge. However, a corner typically may beused as many as six times in the case of triangular patches and thus thenumber of flushes may be significantly different for corners and edgesand the flushing operation may need separate programming in someembodiments.

The pipeline 10 may be cycled for one patch at a time. For each patch,three or four corners or vertices are evaluated and up to four edges maybe evaluated. Thus, in the one embodiment eight parallel inquiries aremade from the edge cache query/corner cache query 20 to the edgecache/corner cache 22. The corner cache can be queried for each of thefour corners of an output control cage and at the same time the fouredges of the output control cage can be queried to the edge cache.

If a given edge or corner is found in the edge cache/corner cache 22, acache hit is detected at diamond 24. In this case, the domain shaderinvocation may be avoided, saving cycles, and possibly in someembodiments improving speed and/or power consumption. If there is nocache hit, then the domain shader invocation is undertaken and, asindicated by the arrow B, the missing edge or corner entry is added tothe corner or edge cache as the case may be.

Flushing of the edge cache/corner cache may be done internally withinthe cache 22. Each time an edge is found to have been reused, it may beflushed. One way of flushing the entry is simply to mark it as availablefor reuse to hold other data. However, in the case of corner caches,each time the corners is used, it would not be flushed. Instead, itcould only be flushed after having been reused the probable number oftimes. Thus, with rectangular patches and rectangular neighborhoods,each corner could be flushed after reuse three times. With triangularpatches in triangular neighborhoods, flushing may occur after reusingfive times. This number of allowed reuses can be tuned empirically bysimulating realistic workloads, instead of setting it to some fixednumber.

An example of an input patch and its one ring neighborhood is shown inFIG. 2. The patch is defined by the corners 14, 16, 47, and 18. Its onering neighborhood is made up of all the patches that surround a givenpatch. Thus the corner 14 may be reused in the ensuing patch 14, 18, 72,in the patch 14, 74, 73, in the patch 14, 15, 12, 74 and in the patch14, 15, 17, and 16. The input control patch shown in FIG. 2 on the leftis then converted by the hull shader into an output control patch shownon the right.

In the case of FIG. 2, no new vertices or corners are generated. Howeverin FIG. 3, showing the same input patch, a different output patch isformed made up of four triangles having a new corner marked N.

The new corner may be given a unique identifier using an appropriatenumbering scheme that does not duplicate existing corner numbers. Thesame number must be used for each of the four successive generations ofthe four triangles that make up the output patch having the commoncorner N. So the left most patch made up of the quad 14, 16, 47 and 18is submitted four times. Each time it is submitted one of the fourtriangles is generated but the same identifier is used for the centercorner for each triangle.

The operations described above in association with the domain shader canalso be done for the tessellator 18. In other words, a cache 22 maysimply be queried by a query 20 before the tessellator 18 stage so thatthe tessellator 18 stage may be bypassed to save cycles in appropriatecores.

FIG. 4 illustrates an embodiment of a system 700. In embodiments, system700 may be a media system although system 700 is not limited to thiscontext. For example, system 700 may be incorporated into a personalcomputer (PC), laptop computer, ultra-laptop computer, tablet, touchpad, portable computer, handheld computer, palmtop computer, personaldigital assistant (PDA), cellular telephone, combination cellulartelephone/PDA, television, smart device (e.g., smart phone, smart tabletor smart television), mobile internet device (MID), messaging device,data communication device, and so forth.

In embodiments, system 700 comprises a platform 702 coupled to a display720. Platform 702 may receive content from a content device such ascontent services device(s) 730 or content delivery device(s) 740 orother similar content sources. A navigation controller 750 comprisingone or more navigation features may be used to interact with, forexample, platform 702 and/or display 720. Each of these components isdescribed in more detail below.

In embodiments, platform 702 may comprise any combination of a chipset705, processor 710, memory 712, storage 714, graphics subsystem 715,applications 716 and/or radio 718. Chipset 705 may provideintercommunication among processor 710, memory 712, storage 714,graphics subsystem 715, applications 716 and/or radio 718. For example,chipset 705 may include a storage adapter (not depicted) capable ofproviding intercommunication with storage 714.

Processor 710 may be implemented as Complex Instruction Set Computer(CISC) or Reduced Instruction Set Computer (RISC) processors, x86instruction set compatible processors, multi-core, or any othermicroprocessor or central processing unit (CPU). In embodiments,processor 710 may comprise dual-core processor(s), dual-core mobileprocessor(s), and so forth.

Memory 712 may be implemented as a volatile memory device such as, butnot limited to, a Random Access Memory (RAM), Dynamic Random AccessMemory (DRAM), or Static RAM (SRAM).

Storage 714 may be implemented as a non-volatile storage device such as,but not limited to, a magnetic disk drive, optical disk drive, tapedrive, an internal storage device, an attached storage device, flashmemory, battery backed-up SDRAM (synchronous DRAM), and/or a networkaccessible storage device. In embodiments, storage 714 may comprisetechnology to increase the storage performance enhanced protection forvaluable digital media when multiple hard drives are included, forexample.

Graphics subsystem 715 may perform processing of images such as still orvideo for display. Graphics subsystem 715 may be a graphics processingunit (GPU) or a visual processing unit (VPU), for example. An analog ordigital interface may be used to communicatively couple graphicssubsystem 715 and display 720. For example, the interface may be any ofa High-Definition Multimedia Interface, DisplayPort, wireless HDMI,and/or wireless HD compliant techniques. Graphics subsystem 715 could beintegrated into processor 710 or chipset 705. Graphics subsystem 715could be a stand-alone card communicatively coupled to chipset 705.

The graphics and/or video processing techniques described herein may beimplemented in various hardware architectures. For example, graphicsand/or video functionality may be integrated within a chipset.Alternatively, a discrete graphics and/or video processor may be used.As still another embodiment, the graphics and/or video functions may beimplemented by a general purpose processor, including a multi-coreprocessor. In a further embodiment, the functions may be implemented ina consumer electronics device.

Radio 718 may include one or more radios capable of transmitting andreceiving signals using various suitable wireless communicationstechniques. Such techniques may involve communications across one ormore wireless networks. Exemplary wireless networks include (but are notlimited to) wireless local area networks (WLANs), wireless personal areanetworks (WPANs), wireless metropolitan area network (WMANs), cellularnetworks, and satellite networks. In communicating across such networks,radio 718 may operate in accordance with one or more applicablestandards in any version.

In embodiments, display 720 may comprise any television type monitor ordisplay. Display 720 may comprise, for example, a computer displayscreen, touch screen display, video monitor, television-like device,and/or a television. Display 720 may be digital and/or analog. Inembodiments, display 720 may be a holographic display. Also, display 720may be a transparent surface that may receive a visual projection. Suchprojections may convey various forms of information, images, and/orobjects. For example, such projections may be a visual overlay for amobile augmented reality (MAR) application. Under the control of one ormore software applications 716, platform 702 may display user interface722 on display 720.

In embodiments, content services device(s) 730 may be hosted by anynational, international and/or independent service and thus accessibleto platform 702 via the Internet, for example. Content servicesdevice(s) 730 may be coupled to platform 702 and/or to display 720.Platform 702 and/or content services device(s) 730 may be coupled to anetwork 760 to communicate (e.g., send and/or receive) media informationto and from network 760. Content delivery device(s) 740 also may becoupled to platform 702 and/or to display 720.

In embodiments, content services device(s) 730 may comprise a cabletelevision box, personal computer, network, telephone, Internet enableddevices or appliance capable of delivering digital information and/orcontent, and any other similar device capable of unidirectionally orbidirectionally communicating content between content providers andplatform 702 and/display 720, via network 760 or directly. It will beappreciated that the content may be communicated unidirectionally and/orbidirectionally to and from any one of the components in system 700 anda content provider via network 760. Examples of content may include anymedia information including, for example, video, music, medical andgaming information, and so forth.

Content services device(s) 730 receives content such as cable televisionprogramming including media information, digital information, and/orother content. Examples of content providers may include any cable orsatellite television or radio or Internet content providers. Theprovided examples are not meant to limit embodiments of the invention.

In embodiments, platform 702 may receive control signals from navigationcontroller 750 having one or more navigation features. The navigationfeatures of controller 750 may be used to interact with user interface722, for example. In embodiments, navigation controller 750 may be apointing device that may be a computer hardware component (specificallyhuman interface device) that allows a user to input spatial (e.g.,continuous and multi-dimensional) data into a computer. Many systemssuch as graphical user interfaces (GUI), and televisions and monitorsallow the user to control and provide data to the computer or televisionusing physical gestures.

Movements of the navigation features of controller 750 may be echoed ona display (e.g., display 720) by movements of a pointer, cursor, focusring, or other visual indicators displayed on the display. For example,under the control of software applications 716, the navigation featureslocated on navigation controller 750 may be mapped to virtual navigationfeatures displayed on user interface 722, for example. In embodiments,controller 750 may not be a separate component but integrated intoplatform 702 and/or display 720. Embodiments, however, are not limitedto the elements or in the context shown or described herein.

In embodiments, drivers (not shown) may comprise technology to enableusers to instantly turn on and off platform 702 like a television withthe touch of a button after initial boot-up, when enabled, for example.Program logic may allow platform 702 to stream content to media adaptorsor other content services device(s) 730 or content delivery device(s)740 when the platform is turned “off.” In addition, chip set 705 maycomprise hardware and/or software support for 5.1 surround sound audioand/or high definition 7.1 surround sound audio, for example. Driversmay include a graphics driver for integrated graphics platforms. Inembodiments, the graphics driver may comprise a peripheral componentinterconnect (PCI) Express graphics card.

In various embodiments, any one or more of the components shown insystem 700 may be integrated. For example, platform 702 and contentservices device(s) 730 may be integrated, or platform 702 and contentdelivery device(s) 740 may be integrated, or platform 702, contentservices device(s) 730, and content delivery device(s) 740 may beintegrated, for example. In various embodiments, platform 702 anddisplay 720 may be an integrated unit. Display 720 and content servicedevice(s) 730 may be integrated, or display 720 and content deliverydevice(s) 740 may be integrated, for example. These examples are notmeant to limit the invention.

In various embodiments, system 700 may be implemented as a wirelesssystem, a wired system, or a combination of both. When implemented as awireless system, system 700 may include components and interfacessuitable for communicating over a wireless shared media, such as one ormore antennas, transmitters, receivers, transceivers, amplifiers,filters, control logic, and so forth. An example of wireless sharedmedia may include portions of a wireless spectrum, such as the RFspectrum and so forth. When implemented as a wired system, system 700may include components and interfaces suitable for communicating overwired communications media, such as input/output (I/O) adapters,physical connectors to connect the I/O adapter with a correspondingwired communications medium, a network interface card (NIC), disccontroller, video controller, audio controller, and so forth. Examplesof wired communications media may include a wire, cable, metal leads,printed circuit board (PCB), backplane, switch fabric, semiconductormaterial, twisted-pair wire, co-axial cable, fiber optics, and so forth.

Platform 702 may establish one or more logical or physical channels tocommunicate information. The information may include media informationand control information. Media information may refer to any datarepresenting content meant for a user. Examples of content may include,for example, data from a voice conversation, videoconference, streamingvideo, electronic mail (“email”) message, voice mail message,alphanumeric symbols, graphics, image, video, text and so forth. Datafrom a voice conversation may be, for example, speech information,silence periods, background noise, comfort noise, tones and so forth.Control information may refer to any data representing commands,instructions or control words meant for an automated system. Forexample, control information may be used to route media informationthrough a system, or instruct a node to process the media information ina predetermined manner. The embodiments, however, are not limited to theelements or in the context shown or described in FIG. 4.

As described above, system 700 may be embodied in varying physicalstyles or form factors. FIG. 5 illustrates embodiments of a small formfactor device 800 in which system 700 may be embodied. In embodiments,for example, device 800 may be implemented as a mobile computing devicehaving wireless capabilities. A mobile computing device may refer to anydevice having a processing system and a mobile power source or supply,such as one or more batteries, for example.

As described above, examples of a mobile computing device may include apersonal computer (PC), laptop computer, ultra-laptop computer, tablet,touch pad, portable computer, handheld computer, palmtop computer,personal digital assistant (PDA), cellular telephone, combinationcellular telephone/PDA, television, smart device (e.g., smart phone,smart tablet or smart television), mobile internet device (MID),messaging device, data communication device, and so forth.

Examples of a mobile computing device also may include computers thatare arranged to be worn by a person, such as a wrist computer, fingercomputer, ring computer, eyeglass computer, belt-clip computer, arm-bandcomputer, shoe computers, clothing computers, and other wearablecomputers. In embodiments, for example, a mobile computing device may beimplemented as a smart phone capable of executing computer applications,as well as voice communications and/or data communications. Althoughsome embodiments may be described with a mobile computing deviceimplemented as a smart phone by way of example, it may be appreciatedthat other embodiments may be implemented using other wireless mobilecomputing devices as well. The embodiments are not limited in thiscontext.

The processor 710 may communicate with a camera 722 and a globalpositioning system sensor 720, in some embodiments. A memory 712,coupled to the processor 710, may store computer readable instructionsfor implementing the sequences shown in FIGS. 4, 5, and 6 in softwareand/or firmware embodiments.

The graphics and/or video processing techniques described herein may beimplemented in various hardware architectures. For example, graphicsand/or video functionality may be integrated within a chipset.Alternatively, a discrete graphics and/or video processor may be used.As still another embodiment, the graphics and/or video functions may beimplemented by a general purpose processor, including a multi-coreprocessor. In a further embodiment, the functions may be implemented ina consumer electronics device.

Radio 718 may include one or more radios capable of transmitting andreceiving signals using various suitable wireless communicationstechniques. Such techniques may involve communications across one ormore wireless networks. Exemplary wireless networks include (but are notlimited to) wireless local area networks (WLANs), wireless personal areanetworks (WPANs), wireless metropolitan area network (WMANs), cellularnetworks, and satellite networks. In communicating across such networks,radio 718 may operate in accordance with one or more applicablestandards in any version.

In embodiments, display 720 may comprise any television type monitor ordisplay. Display 720 may comprise, for example, a computer displayscreen, touch screen display, video monitor, television-like device,and/or a television. Display 720 may be digital and/or analog. Inembodiments, display 720 may be a holographic display. Also, display 720may be a transparent surface that may receive a visual projection. Suchprojections may convey various forms of information, images, and/orobjects. For example, such projections may be a visual overlay for amobile augmented reality (MAR) application. Under the control of one ormore software applications 716, platform 702 may display user interface722 on display 720.

In embodiments, content services device(s) 730 may be hosted by anynational, international and/or independent service and thus accessibleto platform 702 via the Internet, for example. Content servicesdevice(s) 730 may be coupled to platform 702 and/or to display 720.Platform 702 and/or content services device(s) 730 may be coupled to anetwork 760 to communicate (e.g., send and/or receive) media informationto and from network 760. Content delivery device(s) 740 also may becoupled to platform 702 and/or to display 720.

In embodiments, content services device(s) 730 may comprise a cabletelevision box, personal computer, network, telephone, Internet enableddevices or appliance capable of delivering digital information and/orcontent, and any other similar device capable of unidirectionally orbidirectionally communicating content between content providers andplatform 702 and/display 720, via network 760 or directly. It will beappreciated that the content may be communicated unidirectionally and/orbidirectionally to and from any one of the components in system 700 anda content provider via network 760. Examples of content may include anymedia information including, for example, video, music, medical andgaming information, and so forth.

Content services device(s) 730 receives content such as cable televisionprogramming including media information, digital information, and/orother content. Examples of content providers may include any cable orsatellite television or radio or Internet content providers. Theprovided examples are not meant to limit embodiments of the invention.

In embodiments, platform 702 may receive control signals from navigationcontroller 750 having one or more navigation features. The navigationfeatures of controller 750 may be used to interact with user interface722, for example. In embodiments, navigation controller 750 may be apointing device that may be a computer hardware component (specificallyhuman interface device) that allows a user to input spatial (e.g.,continuous and multi-dimensional) data into a computer. Many systemssuch as graphical user interfaces (GUI), and televisions and monitorsallow the user to control and provide data to the computer or televisionusing physical gestures.

Movements of the navigation features of controller 750 may be echoed ona display (e.g., display 720) by movements of a pointer, cursor, focusring, or other visual indicators displayed on the display. For example,under the control of software applications 716, the navigation featureslocated on navigation controller 750 may be mapped to virtual navigationfeatures displayed on user interface 722, for example. In embodiments,controller 750 may not be a separate component but integrated intoplatform 702 and/or display 720. Embodiments, however, are not limitedto the elements or in the context shown or described herein.

In embodiments, drivers (not shown) may comprise technology to enableusers to instantly turn on and off platform 702 like a television withthe touch of a button after initial boot-up, when enabled, for example.Program logic may allow platform 702 to stream content to media adaptorsor other content services device(s) 730 or content delivery device(s)740 when the platform is turned “off.” In addition, chip set 705 maycomprise hardware and/or software support for 5.1 surround sound audioand/or high definition 7.1 surround sound audio, for example. Driversmay include a graphics driver for integrated graphics platforms. Inembodiments, the graphics driver may comprise a peripheral componentinterconnect (PCI) Express graphics card.

In various embodiments, any one or more of the components shown insystem 700 may be integrated. For example, platform 702 and contentservices device(s) 730 may be integrated, or platform 702 and contentdelivery device(s) 740 may be integrated, or platform 702, contentservices device(s) 730, and content delivery device(s) 740 may beintegrated, for example. In various embodiments, platform 702 anddisplay 720 may be an integrated unit. Display 720 and content servicedevice(s) 730 may be integrated, or display 720 and content deliverydevice(s) 740 may be integrated, for example. These examples are notmeant to limit the invention.

In various embodiments, system 700 may be implemented as a wirelesssystem, a wired system, or a combination of both. When implemented as awireless system, system 700 may include components and interfacessuitable for communicating over a wireless shared media, such as one ormore antennas, transmitters, receivers, transceivers, amplifiers,filters, control logic, and so forth. An example of wireless sharedmedia may include portions of a wireless spectrum, such as the RFspectrum and so forth. When implemented as a wired system, system 700may include components and interfaces suitable for communicating overwired communications media, such as input/output (I/O) adapters,physical connectors to connect the I/O adapter with a correspondingwired communications medium, a network interface card (NIC), disccontroller, video controller, audio controller, and so forth. Examplesof wired communications media may include a wire, cable, metal leads,printed circuit board (PCB), backplane, switch fabric, semiconductormaterial, twisted-pair wire, co-axial cable, fiber optics, and so forth.

Platform 702 may establish one or more logical or physical channels tocommunicate information. The information may include media informationand control information. Media information may refer to any datarepresenting content meant for a user. Examples of content may include,for example, data from a voice conversation, videoconference, streamingvideo, electronic mail (“email”) message, voice mail message,alphanumeric symbols, graphics, image, video, text and so forth. Datafrom a voice conversation may be, for example, speech information,silence periods, background noise, comfort noise, tones and so forth.Control information may refer to any data representing commands,instructions or control words meant for an automated system. Forexample, control information may be used to route media informationthrough a system, or instruct a node to process the media information ina predetermined manner. The embodiments, however, are not limited to theelements or in the context shown or described in FIG. 4.

As described above, system 700 may be embodied in varying physicalstyles or form factors. FIG. 5 illustrates embodiments of a small formfactor device 800 in which system 700 may be embodied. In embodiments,for example, device 800 may be implemented as a mobile computing devicehaving wireless capabilities. A mobile computing device may refer to anydevice having a processing system and a mobile power source or supply,such as one or more batteries, for example.

As described above, examples of a mobile computing device may include apersonal computer (PC), laptop computer, ultra-laptop computer, tablet,touch pad, portable computer, handheld computer, palmtop computer,personal digital assistant (PDA), cellular telephone, combinationcellular telephone/PDA, television, smart device (e.g., smart phone,smart tablet or smart television), mobile internet device (MID),messaging device, data communication device, and so forth.

Examples of a mobile computing device also may include computers thatare arranged to be worn by a person, such as a wrist computer, fingercomputer, ring computer, eyeglass computer, belt-clip computer, arm-bandcomputer, shoe computers, clothing computers, and other wearablecomputers. In embodiments, for example, a mobile computing device may beimplemented as a smart phone capable of executing computer applications,as well as voice communications and/or data communications. Althoughsome embodiments may be described with a mobile computing deviceimplemented as a smart phone by way of example, it may be appreciatedthat other embodiments may be implemented using other wireless mobilecomputing devices as well. The embodiments are not limited in thiscontext.

As shown in FIG. 5, device 800 may comprise a housing 802, a display804, an input/output (I/O) device 806, and an antenna 808. Device 800also may comprise navigation features 812. Display 804 may comprise anysuitable display unit for displaying information appropriate for amobile computing device. I/O device 806 may comprise any suitable I/Odevice for entering information into a mobile computing device. Examplesfor I/O device 806 may include an alphanumeric keyboard, a numerickeypad, a touch pad, input keys, buttons, switches, rocker switches,microphones, speakers, voice recognition device and software, and soforth. Information also may be entered into device 800 by way ofmicrophone. Such information may be digitized by a voice recognitiondevice. The embodiments are not limited in this context.

Various embodiments may be implemented using hardware elements, softwareelements, or a combination of both. Examples of hardware elements mayinclude processors, microprocessors, circuits, circuit elements (e.g.,transistors, resistors, capacitors, inductors, and so forth), integratedcircuits, application specific integrated circuits (ASIC), programmablelogic devices (PLD), digital signal processors (DSP), field programmablegate array (FPGA), logic gates, registers, semiconductor device, chips,microchips, chip sets, and so forth. Examples of software may includesoftware components, programs, applications, computer programs,application programs, system programs, machine programs, operatingsystem software, middleware, firmware, software modules, routines,subroutines, functions, methods, procedures, software interfaces,application program interfaces (API), instruction sets, computing code,computer code, code segments, computer code segments, words, values,symbols, or any combination thereof. Determining whether an embodimentis implemented using hardware elements and/or software elements may varyin accordance with any number of factors, such as desired computationalrate, power levels, heat tolerances, processing cycle budget, input datarates, output data rates, memory resources, data bus speeds and otherdesign or performance constraints.

One or more aspects of at least one embodiment may be implemented byrepresentative instructions stored on a machine-readable medium whichrepresents various logic within the processor, which when read by amachine causes the machine to fabricate logic to perform the techniquesdescribed herein. Such representations, known as “IP cores” may bestored on a tangible, machine readable medium and supplied to variouscustomers or manufacturing facilities to load into the fabricationmachines that actually make the logic or processor.

Various embodiments may be implemented using hardware elements, softwareelements, or a combination of both. Examples of hardware elements mayinclude processors, microprocessors, circuits, circuit elements (e.g.,transistors, resistors, capacitors, inductors, and so forth), integratedcircuits, application specific integrated circuits (ASIC), programmablelogic devices (PLD), digital signal processors (DSP), field programmablegate array (FPGA), logic gates, registers, semiconductor device, chips,microchips, chip sets, and so forth. Examples of software may includesoftware components, programs, applications, computer programs,application programs, system programs, machine programs, operatingsystem software, middleware, firmware, software modules, routines,subroutines, functions, methods, procedures, software interfaces,application program interfaces (API), instruction sets, computing code,computer code, code segments, computer code segments, words, values,symbols, or any combination thereof. Determining whether an embodimentis implemented using hardware elements and/or software elements may varyin accordance with any number of factors, such as desired computationalrate, power levels, heat tolerances, processing cycle budget, input datarates, output data rates, memory resources, data bus speeds and otherdesign or performance constraints.

One or more aspects of at least one embodiment may be implemented byrepresentative instructions stored on a machine-readable medium whichrepresents various logic within the processor, which when read by amachine causes the machine to fabricate logic to perform the techniquesdescribed herein. Such representations, known as “IP cores” may bestored on a tangible, machine readable medium and supplied to variouscustomers or manufacturing facilities to load into the fabricationmachines that actually make the logic or processor.

References throughout this specification to “one embodiment” or “anembodiment” mean that a particular feature, structure, or characteristicdescribed in connection with the embodiment is included in at least oneimplementation encompassed within the present invention. Thus,appearances of the phrase “one embodiment” or “in an embodiment” are notnecessarily referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics may be instituted inother suitable forms other than the particular embodiment illustratedand all such forms may be encompassed within the claims of the presentapplication.

While the present invention has been described with respect to a limitednumber of embodiments, those skilled in the art will appreciate numerousmodifications and variations therefrom. It is intended that the appendedclaims cover all such modifications and variations as fall within thetrue spirit and scope of this present invention.

What is claimed is:
 1. A method comprising: domain shading a firstcorner of a first patch; and domain shading a corner of a second patchonly if that corner is not the first corner.
 2. The method of claim 1including providing a unique identifier for each corner of a patch. 3.The method of claim 2 including using an identifier to determine whethera corner has already been domain shaded.
 4. The method of claim 3including storing an indication of which corners have already beendomain shaded in a cache.
 5. The method of claim 1 including determiningwhether an edge and a patch have already been domain shaded.
 6. Themethod of claim 5 including, if an edge has already been domain shaded,skipping the domain shading for that edge in a subsequent patch.
 7. Themethod of claim 6 including using one cache to store edges and cornersalready domain shaded and analyzing all the corners and edges of a patchat one time.
 8. The method of claim 1 including hull shading a givenpatch by adding a new corner to said patch.
 9. The method of claim 8including forming a new corner in the center of a patch and defining aset of four triangles each having the same corner within said patch. 10.The method of claim 9 including automatically determining a uniqueidentifier for said new corner.
 11. A non-transitory computer readablemedium storing instructions to enable a processor to perform a methodcomprising: domain shading a first corner of a first patch; and domainshading a corner of a second patch only if that corner is not the firstcorner.
 12. The medium of claim 11 including providing a uniqueidentifier for each corner of a patch.
 13. The medium of claim 12including using an identifier to determine whether a corner has alreadybeen domain shaded.
 14. The medium of claim 13 including storing anindication of which corners have already been domain shaded in a cache.15. The medium of claim 11 including determining whether an edge and apatch have already been domain shaded.
 16. The medium of claim 15including, if an edge has already been domain shaded, skipping thedomain shading for that edge in a subsequent patch.
 17. The medium ofclaim 16 including using one cache to store edges and corners alreadydomain shaded and analyzing all the corners and edges of a patch at onetime.
 18. The medium of claim 11 including hull shading a given patch byadding a new corner to said patch.
 19. The medium of claim 18 includingforming a new corner in the center of a patch and defining a set of fourtriangles each having the same corner within said patch.
 20. The mediumof claim 19 including automatically determining a unique identifier forsaid new corner.
 21. An apparatus comprising: a processor to domainshade a first corner of a first patch and to domain shade a corner of asecond patch only if that corner is not the first corner; and a memorycomplied to said processor.
 22. The apparatus of claim 21, saidprocessor to provide a unique identifier for each corner of a patch. 23.The apparatus of claim 22, said processor to use an identifier todetermine whether a corner has already been domain shaded.
 24. Theapparatus of claim 23, said processor to store an indication of whichcorners have already been domain shaded in a cache.
 25. The apparatus ofclaim 21, said processor to determine whether an edge and a patch havealready been domain shaded.
 26. The apparatus of claim 25, saidprocessor to, if an edge has already been domain shaded, skip the domainshading for that edge in a subsequent patch.
 27. The apparatus of claim26, said processor to use one cache to store edges and corners alreadydomain shaded and analyze all the corners and edges of a patch at onetime.
 28. The apparatus of claim 21, said processor to hull shade agiven patch by adding a new corner to said patch.
 29. The apparatus ofclaim 28, said processor to form a new corner in the center of a patchand define a set of four triangles each having the same corner withinsaid patch.
 30. The apparatus of claim 29, said processor toautomatically determine a unique identifier for said new corner.